Diseases of the nervous system are responsible for a significant proportion of human health problems. Genetic mutations for several major forms of neurological disease, including epilepsies and neuropathies, have been documented. Due to the human-animal bond, companion animals have health surveillance second only to people, making companion animals and dogs in particular ideal models for many health conditions. Canine models have helped to define the molecular basis and treatment of a number of neurological diseases including narcolepsy, Lafora disease, and lysosomal storage diseases. While the physiology of neurotransmitters and their respective receptors has been extensively detailed for decades, the biology of neurotransmitter synaptic vesicles and associated proteins is just starting to be elucidated. Dynamin 1 (DNM1) is critically important for synaptic vesicle recycling during high level neurological stimulation.
Labrador Retrievers are the most common dog breed in the world, with over 123,760 new US registrations in 2006 alone. Over the last 100 years, with the advent of kennel clubs, dog shows, and very specific dog breed standards, inbreeding within dog breeds has increased dramatically. More than 370 Mendelian diseases have been documented in dogs, with over 70% of them autosomal recessive and 46% breed specific. The high breed specificity is most likely due to deleterious recessive mutations being propagated and concentrated by the founder effect or popular sires being bred repeatedly.
Exercise Induced Collapse (EIC) is a newly characterized syndrome of dogs. The condition has been best described in Labrador Retrievers, but dogs from a number of other breeds are known to have a similar condition. Dogs considered to suffer from EIC usually start to develop signs of an episode 5-15 minutes after the initiation of strenuous “high-excitement” exercise such as retrieving training dummies or birds. At the beginning of the EIC episode the dog starts to lose coordination and develops a ‘wobbly’ gait, which soon progresses to a loss of control of their hind legs. Sometimes the episode affects the entire body, during which the dog is unable to move. The collapse episode usually lasts for 5-10 minutes, and after 30 minutes the dog will have almost completely recovered. EIC affected dogs typically appear to be in excellent physical condition, and usually have very good muscle tone, which is different from many other causes of exercise intolerance.